title: Structure of the guanine nucleotide exchange factor Sec7 domain of human arno and analysis of the interaction with ARF GTPase.
abstract: Sec7-related guanine nucleotide exchange factors (GEFs) initiate vesicle budding from the Golgi membrane surface by converting the GTPase ARF to a GTP-bound, membrane-associated form. Here we report the crystal structure of the catalytic Sec7 homology domain of Arno, a human GEF for ARF1, determined at 2.2 angstroms resolution. The Sec7 domain is an elongated, all-helical protein with a distinctive hydrophobic groove that is phylogenetically conserved. Structure-based mutagenesis identifies the groove and an adjacent conserved loop as the ARF-interacting surface. The sites of Sec7 domain interaction on ARF1 have subsequently been mapped, by protein footprinting experiments, to the switch 1 and switch 2 GTPase regions, leading to a model for the interaction between ARF GTPases and Sec7 domain exchange factors.
authors.affiliation: Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Division, Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA.
authors.forename: E
authors.initials: E
authors.lastname: Mossessova
authors.forename: J M
authors.initials: JM
authors.lastname: Gulbis
authors.forename: J
authors.initials: J
authors.lastname: Goldberg
mesh_terms: D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D005656:Fungal Proteins / Q000737:chemistry*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D006153:Guanosine Diphosphate / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D017421:Sequence Analysis; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
chemical_list: D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; C066755:Sec7 guanine nucleotide exchange factors; C102474:cytohesin-2; D006153:Guanosine Diphosphate; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors